Wok hei' (鑊氣) is a term used in Chinese cooking to describe the unique smoky aroma and flavor that develops when food is stir-fried in a wok over high heat. It is often referred to as the "breath of the wok" due to its ability to infuse food with a smoky, savory taste. This flavor and aroma is created by the combination of high heat, the carbon steel of the wok, and the oils and juices from the food being cooked. It is considered a desirable characteristic in many Chinese dishes and is considered a hallmark of good wok cooking.